Oil extracted from seeds of different varieties of the cultivated Sesamum indicum L and three related wild species, viz S alatum Thonn, S radiatum Schum & Thonn, and S angustifolium (Oliv) Engl, were analysed for their total unsaponifiables and for the contents and composition of the three sterol fractions (desmethyl, monomethyl and dimethyl sterols). The sterols were analysed after saponification by preparative TLC, capillary GC and GC-MS of their TMS ethers. Oils from the wild species contained more unsaponifiable material (2.3-2.4 YO) compared with the cultivated species (1.1-1.3 %). Considerable differences were observed in the total sterol contents and the relative proportions of the three sterol fractions in the oils from the four species studied. Sitosterol, campesterol, stigmasterol and A5-avenasterol were the major desmethyl sterols in all four species. The monomethyl sterol fraction consisted primarily of obtusifoliol, gramisterol, cycloeucalenol and citrostadienol. Cycloartenol and 24-methylene cycloartanol were the predominant dimethyl sterols. Variations in the composition of the three sterol fractions were observed between S indicum oils traditionally pressed by the camel-driven expellers and laboratory extracted oils from the same seeds.

Different chromatographic methods, thin‐layer chromatography (TLC), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS) and normal‐ and reversed‐phase high‐performance liquid chromatography (HPLC), were compared for their ability to separate the different lignans present in fourSesamum species,viz., S. indicum Linn.,S. alatum Thonn., S. radiatum Schum & Thonn. andS. angustifolium (Oliv.) Engl. The advantages and limitations of each method are discussed, and a combination of methods is suggested for qualitative analyses. Two‐dimensional TLC was found to be a valuable qualitative technique and one‐dimensional TLC is useful for preparative purposes. GC is a good supplement for qualitative analysis, but it had many limitations as a quantitative tool—it involves many preparative steps, no suitable internal standard was found to be commercially available and the various lignans had markedly different response factors. GC/MS is a necessary techniqee to confirm the identity of the lignans present. HPLC is a one‐step technique suitable for quantitative analyses, and is fast and simple because it involves direct injection of oil solutions. Reversed‐phase HPLC was unable to separate sesamolin and sesangolin, but a normal‐phase silica column provided satisfactory separation for these two lignans. 2‐Episesalation ofS. alatum, however, did not elute from the normalphase column. Once lignans are identified, a relevant HPLC method can be used for quantitative analyses. Sesamin was present in large amounts inS. radiatum, in considerable amounts inS. indicum andS. angustifolium, and in small amounts inS. alatum. Sesamolin occurred in considerable amounts inS. indicum andS. angustifolium, but only in small amounts in the other two wild species studied.Sesamum alatum was characterized by high amounts of 2‐episesalatin, andS. angustifolium was characterized by high levels of sesangolin.

The fatty acid composition and triacylglycerol profile of seeds of three wild species of sesame viz, Sesamum alatum, Thonn., S. radiatum, Schum & Thonn. and S. angustifolium, (Oliv) Engl. were determined by capillary gas chromatography and high performance liquid chromatography, respectively. Results were compared with those obtained for different pure line and mixed genotypes of S. indicum, Linn., the overall world wide cultivated sesame. Oleic and linoleic acids are the major fatty acids in all samples. The wild species have slightly different saturated acid composition compared to S. indicum. S. alatum contained more palmitic acid (P) while S. radiatum and S . ongustifolium contained more stearic acid. S. alatum also contained higher amounts of oleic acid (0) and lower amounts of linoleic acid (L). The major triacylglycerols were: LLO (20-25%). LLL (10-20%). LOO (15-19%), PLL (8-11 %) and PLO (6-10%). S. alatum was also different from the other three species in having higher percentages of PLO (10.1 %) and 000 (8.7%) compared to 6.3-8.1% of PLO and 3.4-4.9% of 000 in the other three species.

A new, two~limensional thin-layer chromatographic system was established to provide good separation of the unsaponifiable fractions from the seed oils of three wild Sesamum species, IS. alarum, Thonn.; S. radiatum, Schum and Thonn.; and S. angustifolium, (Oily.) Engl.] and of the cultivated S. indicum, L. The system utilizes silica gel plates and n-hexane/diethyl ether (7:3, v/v) and chloroform/diethyl ether (9:1, v/v) as mobile phases in the first and second directions, respectively. The system could be used for qualitative studies and as a preparative technique for subsequent quantitative gas chromatographic separations in chemotaxonomic and related studies on Sesamum spp.

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